content: /* ===========================================================
   * JFreeChart : a free chart library for the Java(tm) platform
   * ===========================================================
   *
   * (C) Copyright 2000-2012, by Object Refinery Limited and Contributors.
   *
   * Project Info:  http://www.jfree.org/jfreechart/index.html
   *
   * This library is free software; you can redistribute it and/or modify it
   * under the terms of the GNU Lesser General Public License as published by
   * the Free Software Foundation; either version 2.1 of the License, or
   * (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
   * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
   * License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
   * USA.
   *
   * [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
   * Other names may be trademarks of their respective owners.]
   *
   * ---------------------------
   * StandardTickUnitSource.java
   * ---------------------------
   * (C) Copyright 2003-2008, by Object Refinery Limited.
   *
   * Original Author:  David Gilbert (for Object Refinery Limited);
   * Contributor(s):   -;
   *
   * Changes
   * -------
   * 23-Sep-2003 : Version 1 (DG);
   * 25-Oct-2007 : Implemented Serializable and equals() method (DG);
   *
   */
  
  package org.jfree.chart.axis;
  
  import java.io.Serializable;
  import java.text.DecimalFormat;
  
  /**
   * A source that can used by the {@link NumberAxis} class to obtain a
   * suitable {@link TickUnit}.  Instances of this class are {@link Serializable}
   * from version 1.0.7 onwards.  Cloning is not supported, because instances
   * are immutable.
   */
  public class StandardTickUnitSource implements TickUnitSource, Serializable {
  
      /** Constant for log(10.0). */
      private static final double LOG_10_VALUE = Math.log(10.0);
  
      /**
       * Default constructor.
       */
      public StandardTickUnitSource() {
          super();
      }
  
      /**
       * Returns a tick unit that is larger than the supplied unit.
       *
       * @param unit  the unit (<code>null</code> not permitted).
       *
       * @return A tick unit that is larger than the supplied unit.
       */
      @Override
      public TickUnit getLargerTickUnit(TickUnit unit) {
          double x = unit.getSize();
          double log = Math.log(x) / LOG_10_VALUE;
          double higher = Math.ceil(log);
          return new NumberTickUnit(Math.pow(10, higher),
                  new DecimalFormat("0.0E0"));
      }
  
      /**
       * Returns the tick unit in the collection that is greater than or equal
       * to (in size) the specified unit.
       *
       * @param unit  the unit (<code>null</code> not permitted).
       *
       * @return A unit from the collection.
       */
      @Override
      public TickUnit getCeilingTickUnit(TickUnit unit) {
          return getLargerTickUnit(unit);
      }
  
      /**
       * Returns the tick unit in the collection that is greater than or equal
       * to the specified size.
       *
       * @param size  the size.
       *
       * @return A unit from the collection.
       */
      @Override
      public TickUnit getCeilingTickUnit(double size) {
          double log = Math.log(size) / LOG_10_VALUE;
          double higher = Math.ceil(log);
          return new NumberTickUnit(Math.pow(10, higher),
                  new DecimalFormat("0.0E0"));
      }
  
      /**
       * Tests this instance for equality with an arbitrary object.
       *
       * @param obj  the object (<code>null</code> permitted).
       *
       * @return A boolean.
       */
      @Override
      public boolean equals(Object obj) {
          if (obj == this) {
              return true;
          }
          return (obj instanceof StandardTickUnitSource);
      }
  
      /**
       * Returns a hash code for this instance.
       *
       * @return A hash code.
       */
      @Override
      public int hashCode() {
          return 0;
      }
  
  }
  